Separate string

i am a biginner of shell scripting.please help me how can i seperate a string in two parts.eg.user given sting is"oi2ehello".i want to make 2 string string1=oi2e and string2=hello

var=testing
echo ${#var}

#!/bin/ksh
> var="oi2ehello"
> echo "${var%%????}  ${var##????}" | read var1 var2
> echo $var1 $var2
oi2eh hello

thanks a lot.....